DEFORMATION AND STABILITY ANALYSIS OF LARGE-SCALE UNDERGROUND CAVITY GROUP UNDER COMPLICATED GEOLOGICAL CONDITIONS

Based on the investigation and geologic exploration information of a hydroelectric power station, the authors set up a computational model which reflects project area steep topography, soft fracture, elaborate underground powerhouse, high earth stress and environmental condition as well. According to earth stress actual measurement results, the initial stress field is played back by linear-elasticity method. To simplify the numerical model, the author adopts an adding stress program and analyses the large-scale caverns in three-dimensional modeling by elastic-plasticity method. The results show clearly that the wall rock between the neighbor cavities,in especial between main power house and tail water houses, the rock wall local plastic failure and destroy region mostly at cavity waist and top angle region, while the stress concentration mostly at top angle region. Both the modeling method and analytic result have a reference sense toward analogy engineering.